23

I wish to use the enumerate/itemize environment within the proof/remark environment, but when I do this the first number/bullet-point is on the same line as the word 'Remark'/'Proof' indented to the right, and all subsequent number/bullet-points are all aligned nicely below.

I think it looks a bit clumsy. I tried adding a double backslash immediately after \begin{proof} but sometimes this means I have the word Proof at the bottom of a page and on the next page the bullet points start, which looks terrible. Is there a way round this?

lockstep
  • 250,273
Paul Slevin
  • 373

5 Answers5

30

here's how it works with amsthm (quoted from the ams author faq):

"When a theorem (proof) begins with a list, how do I keep the first item from running together with the theorem (proof) heading?"

\begin{environment}\leavevmode
\begin{enumerate}\item ...

this will start the list on the next line after the heading.

barbara beeton
  • 88,848
  • 1
    One might ask whether a proof consisting of a long enumerated list (with its shifted margin) makes for good typesetting. And for better understanding as well. – egreg Jun 12 '12 at 13:50
  • @egreg -- didn't say it was a good idea, but an awful lot of authors do it ... – barbara beeton Jun 12 '12 at 13:52
  • When I'm in charge of the editing, this is one of the first things I remove. "We shall divide the proof into four steps.\par Step 1. ...\par Step 2. ..." or similar. The indent and "Step n" are sufficient to give the required emphasis. – egreg Jun 12 '12 at 13:56
  • @egreg -- ams copyeditors make the suggestion to add prefatory text, which improves the appearance. but more important is the fact that enumerate allows one to use a \label and \ref to produce automatically numbered cross-references elsewhere; this reduces the chance for error, especially in books or long articles. – barbara beeton Jun 12 '12 at 15:22
  • 2
    \newenvironment{steps}{\setcounter{step}{0}}{} \newcounter{step} \newcommand{\proofstep}{\par\refstepcounter{step}Step~\thestep.\space\ignorespaces}: this improves consistency. :) – egreg Jun 12 '12 at 15:28
  • @egreg -- very nice idea! sadly, the (la)tex savvy of the ams copyediting staff isn't up to that, aside from which ams has adopted "editorial lite", which often equates to "let the author have what s/he wants" (meaning, what is submitted, if it isn't mathematically invalid). it pains me, but at least we haven't yet got to the point where everything is outsourced. – barbara beeton Jun 12 '12 at 20:04
  • 1
    @barbarabeeton unfortunately this does not answer my question. I still have the environment heading at the bottom of a page, and the list starts on the top of the next page in my compiled document. – Paul Slevin Jun 12 '12 at 22:14
  • @PaulSlevin -- you're correct. and needspace doesn't help because lists are set up to prefer breaks before they start. an explicit page break before the theorem/proof would work, of course, but it's a sledgehammer, and i'm looking for a more "delicate" solution. i'll add it to my answer as soon as i find one; but if anyone else comes up with a good solution before that, i'd be pleased to learn it. – barbara beeton Jun 13 '12 at 15:59
  • @barbarabeeton Thanks, I appreciate your dedication :) – Paul Slevin Jun 13 '12 at 16:23
  • @egreg This not always makes sense. If the statement of the result is an itemized list (with a proper prefatory text, I agree on this), the most natural thing to occur is that the proof consists of items as well, and usually without chance to include a reasonable prefatory text. In such cases I use \begin{proof}\hspace{20mm}, followed by \begin{enumerate}in the next line. I don't know why this works, but from now on, I will use \leavevmode. – Matemáticos Chibchas May 09 '20 at 17:24
3

I usually write

\begin{proof} \hfill
  \begin{enumerate}
    \item
  \end{enumerate}
\end{proof}
user87690
  • 1,009
2

You can use the enumerate environment without the paralist package, like this:

\begin{enumerate}[\hspace{0.25cm} 1. ] 
\item $\nabla f(x^)=0$ 
\item $\nabla^2 f(x^)>0$ (positiva definida) 
\end{enumerate}
diabonas
  • 25,784
Andrea Araujo Sousa
  • 21
2

Just write \mbox{} after \begin{proof} or \begin{remark}. If you wish not to have a page break between proof (remark) heading and proof (remark) content, which is only (starts immediately with) your list, then add the \nolisttopbreak macro below. Or combine \mbox and \nolisttopbreak in a new proof environment.

\makeatletter
\newcommand{\nolisttopbreak}{\vspace{\topsep}\nobreak\@afterheading}
\makeatother

\newenvironment{listproof}[1][\proofname]{\begin{proof}[#1]\mbox{}\nolisttopbreak}{\end{proof}}

\leavevmode seem to have the same effect as \mbox{}, i.e. page breaks are not suppressed.

brac37
  • 133
brac37
  • 21
0

I use the following environment:

\usepackage{paralist}

\begin{proof}
Seja $f: R^n \mapsto R$ duas vezes diferenci\'avel sobre um dom\'inio $S \in R^n$. Se $x^* \in S$ \'e tal que
\vspace{0.2cm}
\begin{compactenum}[\hspace{0.25cm} 1. ]
\item $\nabla f(x^*)=0$
\item $\nabla^2 f(x^*)>0$ (positiva definida)
\end{compactenum}
\vspace{0.2cm}
ent\~ao $x^*$ \'e um m\'inimo local forte de $f$.

\end{proof}

typeset output

It works well.

diabonas
  • 25,784
Andrea Araujo Sousa
  • 21